Vent sexing by an experienced chick sexer can be done at one day of age. This technique is difficult and requires a great deal of experience. If a fast feathering gene has been introduced into the breeding flock, chicks can be sexed by observing the differences in the appearance of the primary wing feathers. The feathers on the wings of the female will be a little longer and in a different pattern than those on the males. Most chickens can not be sexed in this manner.